WebAuth 4.4.2

When I was testing C code coverage analysis tools using WebAuth, I really
should have investigated the segfault that I started getting in the test
suite before releasing 4.4.1. But since valgrind didn't report any
problems, I thought it was something specific to code coverage.

Nope, uninitialized variable inside the WebKDC code. Which valgrind
didn't catch at all for some reason. Now fixed, and I did check for
similar issues, but it's sort of disturbing that valgrind completely
missed it, particularly for a variable whose address is taken and
therefore which I wouldn't think would be optimized away.

Since I hate to release WebAuth to only fix one thing, I also tested
out-of-tree builds for the first time in a while and fixed a pile of
issues around how the Perl module builds work. There's got to be a better
way. Maybe sometime I'll try to come up with some patches to teach
Module::Build how to handle VPATH. I also imported some additional
Autoconf glue that will hopefully help Hurd builds proceed farther,
although I didn't promise anything in NEWS since WebAuth has not yet
successfully built on Hurd.